Characterization of CH4-oxidizing and N2O-reducing bacterial consortia enriched from the rhizospheres of maize and tall fescue

Abstract

CH4-oxidizing and N2O-reducing bacterial consortia were enriched from the rhizosphere soils of maize (Zea mays) and tall fescue (Festuca arundinacea). Illumina MiSeq sequencing analysis was performed to comparatively analyze the bacterial communities of the consortia with those of the rhizosphere soils. Additionally, the effect of root exudate on CH4 oxidation and N2O reduction activities of the microbes was evaluated. Although the inoculum sources varied, the CH4-oxidizing and N2O-reducing consortia derived from maize and tall fescue were similar. The predominant methanotrophs in the CH4-oxidizing consortia were Methylosarcina, Methylococcus, and Methylocystis. Among the N2O-reducing consortia, the representative N2O-reducing bacteria were Cloacibacterium, Azonexus, and Klebsiella. The N2O reduction rate of the N2O-reducing consortium from maize rhizosphere and tall fescue rhizosphere increased by 1.6 and 2.7 times with the addition of maize and tall fescue root exudates, respectively. The CH4 oxidization activity of the CH4-oxidizing consortia did not increase with the addition of root exudates. The CH4-oxidizing and N2O-reducing consortia can be used as promising bioresources to mitigate non-CO2 greenhouse gas emissions during remediation of oil-contaminated soils. © 2021, The Korean Society for Microbiology and Biotechnology